The invention relates to a fuel injection nozzle of the general type described. Particularly suitable for effective electronic Diesel injection regulation is the provision of a transducer in the injection nozzle to detect injection tuning, either the onset of injection, (that is, the opening of the nozzle) or to detect the injection needle stroke duration, (that is, the travel of the nozzle needle over time) and to generate a signal therefrom.
A contact-free distance measurement with an inductive receiver is already known, which criterion can be used for measuring the needle stroke. The significant expense of a carrier frequency amplifier and the highly distance-dependent sensitivity of the measurement signal very probably militate against a commercially-oriented application thereof.
Studies have shown that a transducer which functions on the opto-electronic principle is not commercially practicable because initially single oil drops and later air bubbles or foaming of the oil can cause problems.
A transducer functioning by the electrostatic principle has been studied; such transducer comprises a metallic inner electrode, a cylindrical dielectric and the compression spring of the nozzle holder as a second electrode. As a result of the spring movement upon injection, a voltage appears at the transducer which, however, only becomes usable as a signal for the onset of injection after appropriate further processing thereof has been performed.